dev-haskell/diagrams-lib: allow numinstances-1.3

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
eclass/haskell-cabal.eclass: add a hint about 'haskell-updater' when 'ghc-pkg check' detects badness.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>